Broken Bolt Results in Japan Self-Defense Force's Helicopter Crash

2019-10-21 | Class : 螺絲

Last year Japan Self-Defense Force's attack helicopter crashed into a civilian house because the metal bolts for securing the helicopter blades ruptured and caused the blades to come off. The bolts originally had embedded pins that spinned with the bolts as the blades rotated.

The investigation result released on September 27, 2019 revealed that the failure of the rust inhibitor caused the pins to jam with other components and disabled the blades' rotation before the accident occurred. Bolts could rupture because of friction generated from their rotation. On the other hand, the investigators did not rule out the possibility of the bolts already having cracks for a certain cause before they were installed.

The helicopter crashed into a civilian house in a test flight on February 5, 2018. The accident led to the injury of a girl in the house and the death of two helicopter crews.